Hvac Duct Smoke Detector Requirements

A duct smoke detector should shut off a typical blower and fresh air and turn on the exhaust duct detectors aren t a replacement for room sensors if the duct system is designed to carry more than 2000 cfm 5 tons nominal of air you need one in the return if imc is being followed and the supply if nfpa is being followed.

Hvac duct smoke detector requirements.

Summary duct smoke detector requirement air moving systems supplying air in excess of 2 000 cfm to enclosed spaces within buildings shall be equipped with an automatic shutoff. The ashrae handbook of smoke control engineering nfpa life safety book for health. A heating ventilating or air conditioning hvac fan motor overheats and resulting smoke is sensed by the duct smoke detector installed in the main supply duct. Duct smoke detection may be useful in preventing injury and property dam age in instances such as the following.

There are other smoke detector safety concerns in air conditioning and heater systems and they can be found in the following reference material. Nfpa 72 also states that a duct smoke detector is not allowed to replace an area smoke detector mainly because if the air handling unit ahu is not running the detector would not detect smoke. The duct smoke detector is equipped with an auxiliary relay. Duct smoke detectors are not required if the occupied space is served by an area smoke detector system.

Ventilation fan systems used to remove air from the inside of the building to the outside of the building.